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It&rsquo;s no longer enough for a race bike to be light and stiff&mdash;now it also needs to slice through the wind. Because cyclists use the majority of their power to overcome wind resistance, aero frames are faster in nearly &shy;every situation,&shy; leading to a new category for performance bikes. A &shy;marriage between <a href="http://www.bicycling.com/bikes-gear/new-bike-gear-previews/need-speed-20... bikes</a> and standard road racers, these models are light, efficient, and <a target="_blank" href="http://www.a2wt.com/Bicycle.htm">wind-tunnel certified</a>.<br />
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The execution of the aero road bicycle has taken time. Many early models were heavy, not stiff enough, or transmitted too much road noise. But now, &shy;several generations later, the bikes are more refined, riding with characteristics similar to traditional frames. For our first-&shy;ever Editors&rsquo; Choice award in this category, we gathered some of 2012&rsquo;s best examples. In addition to extensive road evaluations by our test riders&mdash;our practice with every bike we test&mdash;&shy;we took all five to North Carolina&rsquo;s A2 Wind Tunnel to evaluate the aerodynamic&shy; characteristics of each, comparing them with a 2012 Editors&rsquo; Choice award-winning race bike, the Specialized Tarmac S-Works SL4. In the tunnel, there was a clear winner, but the differences between bikes were minimal. That means you should base your purchasing decision on ride characteristics and fit rather than on aerodynamics. If you want to go faster, one of these slippery machines will speed up your next competitive ride&mdash;be it a race or Strava segment.<br />
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<a href="http://bicycling.com/bikes-gear/bikes-and-gear-features/cheating-wind-1"... to the data &raquo;</a><br />

<img alt="" src="http://www.bicycling.com/sites/default/files/images/editors_choice_12.gif" style="float:right;" /><br />
<h2><strong>EDITORS'&nbsp;CHOICE WINNER<br />
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Our test riders didn&rsquo;t like the <a href="http://www.bicycling.com/cervelo-s5-vwd-aero-road-bike">S5&rsquo;s</a> looks (new graphics for 2013 help to mitigate 2012&rsquo;s lab-coat aesthetics), but once we were in the saddle, the gorgeous ride took our mind off appearances. &ldquo;It&rsquo;s not just great &lsquo;for an aero road bike,&rsquo; it&rsquo;s a great road bike, period,&rdquo; said one rider. The S5 posted the top performance at A2, and on the road its ride was the most refined of the group. The handling was quick yet predictable, perfect for both crits and road races. Where the other four bikes ranged from firm to stiff and gritty to raw, the S5 felt comfortable, damped, and supple. It felt a bit slower than the superstiff <a href="http://bicycling.com/specialized-s-works-venge-sram-red">Specialized Venge</a>, but the trade-off is that you&rsquo;ll feel less beat up as the miles pile on&mdash;a swap we&rsquo;ll happily make. Even if it was damped in the saddle, testers also called out the Cerv&eacute;lo for efficiency. The <a href="http://www.bicycling.com/bikes-gear/bikes-and-gear-features/shimano-reve... behaved like that of any modern race bike&mdash;it didn&rsquo;t feel especially stiff, but it immediately reacts to changes in power. <br />
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<strong>PRICE</strong>: $9,500 <br />
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<strong>WEIGHT:</strong> 14.6 lb. (54cm)<br />
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<strong>INFO:</strong> <a target="_blank" href="http://cervelo.com">cervelo.com</a>

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<strong>Our Testing Protocol. </strong><i>&mdash;Matt Phillips</i><br />
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&mdash;In the <a href="http://bicycling.com/bikes-gear/bikes-and-gear-features/why-aerodynamics..., everything, no matter now small, makes a difference. Even details like saddle height and the thickness of the bar tape can alter the numbers. <a href="http://bicycling.com/bikes-gear/bikes-and-gear-features/cerv-lo-s5-vwd-d... David Kennedy says he has found that even the direction the bar tape is wrapped can affect results. We controlled every variable that we could, but our data may not match that collected in other tests.<br />
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&mdash;We tested each bike two ways: with the wheels you&rsquo;ll get when buying the bike, and also with a control set of wheels&mdash;<a href="http://video.bicycling.com/video/Zipp-401-Wheels">Zipp Firecrest</a> 404 tubulars shod with Vittoria EVO CX 23mm tires. Every bike (all were size 54cm) was tested with a Fi&rsquo;zi:k Arione saddle set to the same height and setback. We also cut steerer tubes to the same height and installed the stem at the same angle. While testing the frames with matching components may have yielded different results, we believe that this method let us better test the bikes you will buy. <br />
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&mdash;We tested without bottles or cages. While these items definitely affect overall drag numbers, we chose to test without them in order to eliminate a large variable. <br />
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&mdash;Some manufacturers claim their aerodynamics are optimized to work with a rider, but we tested the bikes without a rider or dummy. A human isn&rsquo;t consistent enough to maintain the same position on each of six bikes; even a subtle shift in the saddle or head tilt could skew the data. <br />
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&mdash;We tested the bikes with a straight-on headwind, and with the wind coming from five-degree increments up to 20 degrees on both sides of the bikes. In the real world, the effective wind angle is a combination of both the speed and direction of your travel, and the wind&rsquo;s speed and direction. If you&rsquo;re traveling at 20 mph and there is a 20-mph wind blowing from 20 degrees, the effective wind angle is 10 degrees. If a rider is traveling at 20 mph and there is a 5 mph wind blowing from 30 degrees, the effective wind angle is TK. Engineers disagree on the question of which is the average effective wind angle that most riders experience, but most believe that it&rsquo;s between five and 15 degrees. <i><br />
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